The transmissible spongiform encephalopathies (TSEs or prion diseases)are fatal untreatable neurodegenerative diseases such as scrapie, Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy and chronic wasting disease (CWD). TSE pathogenesis involves the accumulation of an abnormal misfolded protein, called PrPres, in infected hosts. This fiscal year, we have extended studies of the influence of chaperone proteins and peptides on PrPres formation. One chaperone protein was found to act as an inhibitor.